New Rifle Question, Please Help

[fishnfrank]

I'm going to let you know right off the bat that I don't really know much about blackpowder guns. I do want to get into it though. So please answer me this question. Is it true and if it is, why are some of the new blackpowder rifles not legal in some states. I sure would hate to buy a rifle and not be able to hunt with it. Please help me out here.